Transponder XPNDR for Boeing 737NG. Consisting on the following elements:

* 1 front panel size 45x55 mm
* 1 auxiliary panel
* 1 key (1 front + 1 rear pieces)

Components needed (not included):

* 2 ON-OFF switches
* 1 OMROM B3F 4050 keyswitch
* 4 display digits
* 1 rotary switch (12 positions, 1 circuit)
* 2 CTS288 encoders